Pneumatically operated clamps are used in a variety of industries for securing objects in a position for various purposes. In automobile manufacturing, for example, stamped metal body parts are assembled on a pallet, wherein various pre-fabricated individual initial components or other parts of an automobile body are positioned on the pallet and clamped in place. Once clamped, the individual initial components are welded together, therein generally defining the automobile body. A typical pallet has at least four clamping locations (e.g., one clamping location is assigned to each of four corners of the automobile body), wherein at least one pin clamp apparatus is precisely affixed to the pallet at each clamping location via a riser (e.g., a weldment having precise dimensions).
Accordingly, once clamped in place by the pin clamps, the precise positioning of the individual initial components of the automobile body is assured at an initial station along an assembly line, and subsequent positioning and welding of subsequent components to the automobile body can be further generally assured, assuming the pin clamp(s) retain their clamping force as the automobile body progresses along the assembly line. Once assembly of the automobile body is complete, the pin clamps release the automobile body from the pallet for subsequent assembly, such as for painting and final assembly.
Conventionally, the pallet is referenced at a hardened steel position on the pallet, and the risers (and associated pin clamps) are further referenced to the hardened steel position. Typically, the pin clamps are pneumatically operated, wherein initial clamping of the pin clamps is performed at the initial station by pneumatic pressure. In order to maintain the precise positioning of the automobile body along the assembly line, the pin clamps at the four corners must typically remain clamped until assembly of the automobile body (often referred to as a “white body”) is finished. However, once the initial components are positioned and welded at the initial station, pneumatic pressure is removed from the pin clamps so that the pallet can be transferred to subsequent welding and assembly stations. Pneumatic pressure is typically not reintroduced to the pin clamps until the white body is completely assembled, which is when the white body is unclamped from the pallet and ready for the subsequent assembly process. Conventionally, the white body is held in place by the clamping pins during the absence of pneumatic pressure via complex mechanical components within the clamping pin apparatus, such as cams, gears, or other mechanisms.
During initial setup and/or day-to-day operation in the assembly process, it is also sometimes necessary to modify an orientation of the pin clamps for various reasons, such as to permit access for robots to enter areas of the automobile body otherwise blocked by a pin clamp. Conventionally, a pin clamp is configured to be initially secured to the riser, whereby the orientation and referencing of the pin clamp with respect to the hardened steel position on the pallet is accurately measured. Conventional pin clamps have been provided that can clamp a workpiece with respect to a mounting surface of the pin clamp, or in a position that is 180-degrees opposed to the initial position. As such, when clamping is desired at positions other than the initial or 180-degree opposed position of the pin clamp, the riser is typically modified or changed, and the pallet is referenced again, at significant cost and consumption of time. Such a change can cause many problems, especially when a large number of pallets are involved (e.g., 800-1000 pallets are not uncommon in an assembly line). Furthermore, customized risers can be quite expensive, where the customized riser is designed to provide specialized location capabilities.